NOVA NOTES, the newsletter of the Halifax Centre of the Royal Astronomical Society of Canada, is published bi-monthly in February, April, June, August, October, and December. The opinions expressed herein are not necessarily those of the Halifax Centre. Material for the next issue should reach the editor by July 31th, 1996. Articles on any aspect of astronomy will be considered for publication. "Letters to the Editor" or to our resident expert: GAZER are also most welcome. Contact the editor at:
INSIDE THIS ISSUE...
Map to St. Croix Observatory Site
Meeting Report: May 96 by Pat Kelly
Six Bright Comets by Roy Bishop
St. Croix Observatory Status Report
Hale-Bopp Summer Finder Chart (not in the web version of Nova Notes)
Notice of Meetings and Other Stuff
Map to St. Croix Observing Site - Scheduled
Observing Saturdays After the New Moon
BY DAVID CHAPMAN
Since my last report, Comet Hyakutake has rounded the Sun and passed into the Southern sky, but this truly spectacular comet has not vanished from our thoughts, as many of us have been processing our slide and print exposures of the comet and there has been almost continuous production of photographic prints. The photos by Darren Talbot and Dave Lane have been selling about as fast as they make 'em, and all proceeds are going to the Observatory Fund. (Paul Gray is offering prints of his very fine Tri-X exposures, as well.) I finally developed my Ektachrome 400 slides of the comet, taken in conjunction with Dale Ellis with my camera mounted piggy-back on his telescope with long-focus lenses kindly supplied by our friend and colleague Harold Merklinger. We were taken aback at our own accomplishments, and encourage other budding comet-photographers to prepare for Comet Hale-Bopp next year.
May's meeting was a Members' Night (i.e. no main speaker) with "comets" as a special theme (see Pat Kelly's report in this issue). It is good to have these nights from time to time, as they provide an opportunity to share our observations and activities with each other and the general public. They are fairly relaxed occasions, with a lot of discussion and banter.
I take pleasure in announcing that the winner of the Centre's Burke-Gaffney award for the best Nova Notes Article published in 1995 is Diane Brooks, for her article "The Astronomy of Native Americans". Diane, who now lives in Ottawa but retains her membership with us, will receive a certificate and a book prize.
With the arrival of warmer weather, you should expect to find observers at St. Croix on almost any clear night. If you wish to join them, contact the Observing Chairman Paul Gray, or Dave Lane, whose new 18" telescope has temporarily relieved his aperture fever, from which he suffers from year to year. Public Observing is planned for Dollar Lake on 19 July and 24 August. See the notice on the back cover of this issue for details.
Speaking of the St. Croix Observatory, the Observatory Committee has finalized plans for the site and are requesting a building permit. Shawn Mitchell is looking for site workers (any assistance would be welcome); for those unable to donate their time and labour, Pat Kelly will gleefully explain how you can make a tax-exempt donation to the cause.
Next month (21 June), fellow member
Larry Bogan will explain how orbits of asteroids and comets can
be deduced from positional observations. As a physicist, I know
that this must be possible, but I have always been curious as
to what the exact procedure is. I am looking forward to this,
especially as it is our last opportunity to meet as a group before
the summer break. If you can't make it, don't forget Nova East
MEETING REPORT: MAY 96
BY PAT KELLY
Well, here I am, keyboard positioned under my hands, fingers eagerly awaiting instructions from the brain, to commit once again to paper, the goings-on of the Halifax RASCals.
The executive meeting, normally an affair best suited to those with insomnia, had a few interesting items this month. Our public observing sessions at Dollar Lake Provincial Park are listed on the province's newly produced tourism poster. You have probably seen them in service stations and convenience stores; a road map of Nova Scotia on the top and half of a square metre of 6 point text listing the events on the bottom. Well, if you look carefully you will find us listed as "The Sky at Night" or words to that effect, with the event being held in Elderbank. Apparently the tourism department figures that there is no point listing provincial parks on a tourist map, so we get listed under nearest place that has a post office. Granted, they are already one step ahead of themselves, because originally, they had both our events as well as Dollar Lake Days as being held in Aldershot, just north of Kentville. Well, one should not be too surprised, because after all this is the same department that came up with the brilliant idea of supporting licensing fees for use of the Bluenose image. Need I say more.
Approval was also given to apply for a building permit for the first two buildings that are to be constructed at the new observing site. In true Ferengi form, Shawn and Dave distributed two sets of plans. The ones for the executive and members, showing the communal roll-off observatory and the warm room; and the one for the building inspector showing the locations of Shed #1 and Shed #2.
The last item of interest is that the recipient of the Burke-Gaffney Award for 1995 was announced, but more on that later.
Off now to the regular meeting. The auditorium was dominated by Dave Lane's new telescope, a hand-made 18" Newtonian. This is a beautiful instrument, made in a manner similar to his previous one; wood with aluminum rods to form a truss to the housing for the secondary and eyepiece. The truss was wrapped in a large black shroud, no doubt in mourning for its predecessor, which has not collected any photons since first light on the new instrument. One of the "advantages" of Dave's new scope is that he has trouble carrying all of the bits and pieces from his vehicle to his apartment and back again. As a result, rumour has it that it hasn't been back into his lodgings since its first trip out. As a result, the "Scopemobile" is always ready to observe at a moment's notice.
Next to the scope was a folding stepladder. This accessory is a godsend for those people, who like the scope's owner, are vertically challenged when it comes to large telescopes. Dave is going to have to be careful though, as several of the larger members of the club find the telescope very comfortable without a ladder at all. Better yet, should any of us decide to walk off with this beast, our liability insurance will cover hernias!
The regular meeting started with the previously-mentioned Burke-Gaffney Award. This year's winner is Diane Brooks. There was a short explanation, for those who may not know Diane, that she has been living in Ottawa for the last few years and that although her husband, Randall, had switched his life membership to the Ottawa Centre, she had kept hers with Halifax. There was some relief expressed that we had not given the award to a member of another centre!
Paul Gray was up next with "What's Up". He explained that the next month was really going to be very quiet. Reading between the lines, what he really meant was that there were no good meteor showers coming up! It had been decided to resume regularly scheduled observing sessions at the new St. Croix site. They will be held on the Saturday following the new Moon. People who want to make sure that it is on should call either Paul Gray (864-2145) or Dave Lane (443-5989). You can also call them on any other clear night to see if there will be observing. (If there is no answer, chances are they are already on their way!) A map and directions to the site can be found elsewhere in this issue.
Shawn Mitchell then went over the plans for observatory construction for the summer. One item which had been added was a gate across the entranceway. He displayed a map of the site and of the structures that will be built. Dave Lane had resurveyed it, since their first attempt ended up with two points that should have been in the same spot being about 25 metres apart. Dave noted that back in early Canadian history, it was astronomers that were responsible for a lot of the surveying to make maps and, that based on his experience, it was a wonder that anyone could use them. Obviously, to have it done properly the first time, we should have had Nat Cohen do it with his sextant!
The main event for this meeting was a retrospective of Comet Hyakutake. Mary Lou Whitehorne kicked things off with a series of beautiful slides. She admitted that she had not done any astrophotography in quite some time, but it was obvious that she had not lost her touch. On one of the slides the colour was very pronounced, with a blue ion tail, greenish coma and yellowish dust tail. She said that when looking at the comet through Roy's telescope, there was also an area near the nucleus that was pinkish in colour.
Roy was up next. Other members are advised that on future slide displays, they should always try and get on before Roy as he is a tough act to follow! His slides started further back in time, when the comet was still quite low in the sky. He also had some spectacular shots of the disconnection event in the tail, and one that showed the tail stretching for 54 degrees! Roy wrapped his slides up with a nice shot from twenty-six years ago, showing Comet Bennett in a dawn sky. It turns out that Comet Bennett.
David Chapman showed a few shots of the comet that were taken at the Beaverbank site. One was an neat composite shot. At least composite in the sense that the scope, camera and lens were owned by three different people! There was also a rather bizarre "landscape" shot showing a small fuzzy patch in the sky, which was the comet, and the convoluted trail of a red light. It was explained that Dave Lane had tried to print out "1996 B2" with a red flashlight. One could see that with averted vision (and some imagination). Dave, a hint for next time: it is OK to turn the light off between letters.
Dave was up next, and before showing some slides, he displayed the 16x20 prints that had been made from one of Darren Talbot's comet photos (and which were available for $15). He also showed off the three 8x10 photos which were also for sale at $5 each. All of the proceeds are going to the observatory fund, and so far this project has been a great success. He explained that his slides had been shot from prints so the color was not quite as nice as in the originals. Some of the shots had been taken from Mary Lou's cottage at Bayswater, where their observing had been interrupted by the local police. It turns out that someone in the area had seen some nocturnal activity on the beach and had thought there might be some drugs being smuggled into the country! Dave also showed a series of images that had been taken on the same night, starting with a one second exposure and progressing all the way up to twenty minutes.
Last up in the "Comet Hyakutake, This Was Your Life! show was Clint Shannon who had a beautifully framed photograph of the comet that he had taken. It was complete with his signature in gold ink! It would look great hanging in any home, astronomer's or otherwise.
Roy was back up with some slides that he had taken at the Winter Star Party. While I had already seen them at a meeting of the Minas Astronomy Group, they were just as interesting the second time around. One of the more interesting slides that he had taken before actually getting to the site of the star party was of a sign that was on the side of the road in the Everglades. It warned people that there were wild alligators and that people were not to feed or molest them. Considering the size of some of the alligators that Roy saw, one had to wonder if you would get a ticket if you were eaten by one! There were lots of interesting telescopes on display, including some real monsters.
As a prelude to get us ready for Comet Hale-Bopp, Dave Lane showed us a video animation of the path that the comet would take during the next year. It should be easily visible this summer and by September, may be visible to the naked eye. Finder charts for the summer months were also available for anyone who wanted one. Stay tuned for updates!
The meeting wrapped up with Dave explaining
the details of his new telescope. he found that if he made a graph
of the aperture of his telescope versus time, the aperture is
increasing at the rate of one inch per year. I can hardly wait
until he retires!
SIX BRIGHT COMETS:
BY ROY BISHOP
Since the spectacular apparition of Comet Hyakutake earlier this year, I have heard people wondering how "the Great Comet of 1996" compares to those of earlier years. I have seen six bright comets, and offer the following comments on the earlier visitors.
The first comet in my observing notes is Arend-Roland (1957 III). On April 29 that year it was in the northwestern evening sky just above Perseus, nearly in the same position as was Hyakutake at the end of March 1996! However, Arend-Roland had already passed perihelion and was then backing away from the Sun and fading. On that April evening 39 years ago, Arend-Roland was near 3rd magnitude, and displayed a dust tail about 10 degrees long.
Later that same year (1957), on the evening of August 13 while standing by the shore of a lake, I discovered a bright, naked-eye comet low in the northwestern evening twilight between the hind feet of Ursa Major. In the newspaper a day later I learned that this was Comet Mrkos (1957 V). Like Arend-Roland, it had already passed perihelion and was heading back from whence it came. Near magnitude +2, Comet Mrkos displayed a bright dust tail about 5 degrees in length.
The next bright comet was Ikeya-Seki (1965 VIII). This Sun-grazer passed two-thirds of a solar radius from the Sun's surface on October 21, 1965 and became visible in the dark, pre-dawn sky by early November. Sherman Williams and I photographed it in the cold pre-dawn sky of November 3. That morning Ikeya-Seki was sprawled across the southeastern sky in the vicinity of Corvus and Crater, its immense, gently-curved tail spanning about 18 degrees. Since Ikeya-Seki was then about 1 AU from Earth, its coma was very small in angular extent, and its overall brightness on that November morning was near magnitude +1.
Next came Comet Bennett (1970 II). Bennett moved north out of the dawn twilight in late March 1970. I first saw it on March 26 in Aquarius, and followed it for over five months, until September 4 when it was a telescopic blip about 10 degrees from Polaris. With a bright dust tail spanning over 10 degrees, Bennett was the classic image of a comet. At its best in late March/early April, Bennett was about magnitude +1.
Comet West (1976 VI) rose out of the dawn twilight late in the winter of 1976. I first saw it in the cold, red dawn sky of February 29. At magnitude -1 the bright white dust tail near its nucleus remained visible in binoculars up until only 8 minutes before sunrise! A week later West was in view at the beginning of twilight, and displayed a spectacular curved tail more than 20 degrees in length. (A photo taken that morning by Sherman Williams appears on the cover of the 1986 Observer's Handbook). At that point Comet West was in Pegasus, only a few degrees from where Comet Bennett had been at its best 6 years earlier. Like Ikeya-Seki and Bennett, West was in the morning sky, thus few people saw it!
And then there was Comet Hyakutake of March 1996. When the clouds finally parted over Nova Scotia on the evening of March 24 revealing Hyakutake at its closest point to Earth (a mere 0.10 AU), the view from dark country skies was awesome (to use a popular adjective). Near magnitude 0.5, with a large coma displaying intricate structure, and with an ion tail spanning more than 40 degrees, Hyakutake takes the prize as the most spectacular comet I have seen (although Comet West was a close second). Moreover, unlike the earlier five bright comets which were at their best near the twilight portion of the sky, Hyakutake at its best was sprawled through the zenith at midnight!
In retrospect, we were fortunate that the four nights previous to March 24 were mostly cloudy. This allowed Hyakutake to sneak up on Earth behind a curtain of cloud, a curtain which lifted at the moment the comet was closest, leaving a superbly transparent sky for that magical night. Anyone who did not avail themselves of dark country skies after moonset in the early hours of March 25 missed the sight of a lifetime! (Although the view was nearly as good in the after-moonset hours of the next two nights). David Chapman put it well later that day when he pleaded with people: "GET OUTTA TOWN! You owe it to yourself."
The ultimate compliment paid to Comet
Hyakutake was by Nat Cohen: "I perceive this to be a real
ST. CROIX OBSERVATORY STATUS REPORT:
BY: DAVID LANE
Since the last observatory report, considerable progress has been made. The design of the observatory was completed and the site has been surveyed. These two tasks, which resulted in the two drawings printed in this issue of Nova Notes (sorry, these drawings are not in the web version of Nova Notes), were used to apply for the building permits.
I'm pleased to announce that we have
received our permits from the Hants West Municipal Office. Shawn
Mitchell has met with a local contractor and with any luck, the
gravel work and the concrete slabs, upon which the buildings will
be built, will be completed by the time you read this.
Construction of the two buildings will be completed by centre members over the summer and early fall. For those who have not indicated that they are willing to help with the construction, please call Shawn Mitchell (865-7026).
You will also find on the front cover of this issue a map showing how to find the observatory site. The map shows the area near the observatory site, which is located off exit 4 of Highway 101 between Upper Sackville and Windsor.
Fund raising is continuing. We thank
those who have already donated towards the observatory project.
You should have your income tax receipts by now. However its not
too late to write that cheque! As mentioned, we were (still are!)
selling enlargements of the comet photos taken by Darren Talbot
and myself. This effort has raised $750 for the observatory project
Date: Regular Meeting - Friday, June 21 at 8pm; 7pm for the council meeting.
Place: Lower Theatre, Nova Scotia Museum of Natural History, Summer Street, Halifax. Access is from the parking lot.
Topic: Main Speaker: Dr. Larry Bogan
of Acadia University (Wolfville, NS). His talk is titled "Principles
of Orbit Determination." In his talk he will explain how
the orbits of solar system objects are determined given a series
Nova East 96:
Our annual star party will be held the weekend of August 16-19
at Fundy National Park, New Brunswick. See the brochure included
with this issue of Nova Notes (if its missing, call Paul Gray
at 864-2145 for a copy).
Astro Atlantik 96:
This star party, organized by "Astronomy New Brunswick"
(the alliance of astronomy groups in New Brunswick), will be held
the weekend of June 21-23 at Fundy National Park (Chignecto South
Campground). At this late date, if you need directions or other
information, you had best call Adrien Bordage at 506-635-3004.
David Lane (443-5989) is attending can also provide information.
Highland Star Party 96:
This star party, organized by the "Cape Breton Astronomical
Society," will be held the weekend of August 9-12 at the
Highlands National Park (Cape Breton). For information, write
to John Reppa, 131 Green Acres Dr., Sydney River, N.S., Canada,
B1S-1K5 (phone: 902-562-2772). Or, access their website at: "http://www.cbnet.ns.ca/cbnet/comucntr/astronomy/cbas.html"
The Centre is sponsoring two public observing sessions at Dollar
Lake Provincial Park (near Elderbank in the Musquodoboit Valley).
These will be held on Friday, July 19th (if cloudy,
July 20th) and August 23rd (if cloudy, August
24th). We will need your help in presenting the universe
to the general public. To volunteer, call Blair MacDonald (445-5672)
or Paul Gray (864-2145).
The Halifax Center has several telescopes
for loan to members. These include a Celestron C8 equipped for
photography, a Questar 3.5", a 4" rich-field telescope,
a 4" Maksutov-Cassegrain, and a 10" Dobsonian. Contact
the Observing Chairman, Paul Gray, for further information.
Honorary President Dr. Murray Cunningham
President David Chapman 463-9103
1st vice-president Blair MacDonald 445-5672
2nd vice-president Shawn Mitchell 865-7026
Secretary Tom Harp 465-4928
Treasurer Ian Anderson 678-8009
Nova Notes Editor David Lane 443-5989
National Representative Pat Kelly 798-3329
Librarian Clint Shannon 889-2426
Observing Chairman Paul Gray 864-2145
Councilors Darren Talbot 443-9373
Dr. David Turner 435-2733
Mary Lou Whitehorne 865-0235